Rotary printing machines



Sept. 1, 1959 P. KNOPS ET AL 7 ROTARY PRINTING MACHINES 2 Sheets-Sheet 1 Filed May 12, 1958 v P 1959 l. P. KNOPS EIAL 2,901,970

" ROTARY PRINTING MACHINES Filed May 12, 1958 2 Sheets-Sheet 2 United States Patent 2,901,970 H ROTARY PRINTING MACHINES Ivan Peter Knops, Twickenham, and DavidChristopher Camps, Long Ditton, England, assignors to the De La Rue Company Limited, a company of Great Britain Application May 12, 1958, Serial No. 734,533

Claims priority, application Great Britain August 7, '1957 6 Claims. (Cl. 101-247) This invention relates to rotary printing machines and especially to an arrangement whereby the printing pres sure can be adjusted within desired limits.

The usual method of varying the printing pressure is by adjusting the make ready, i.e. the amount of packing on the impression cylinder beneath its covering-of resilient material. This method, however, is somewhat difficult to put into effect as it requires that the machine must be stopped and the make ready varied at any time when a pressure variation is required. 7

An object of this invention is to provide means whereby the printing pressure can be varied readily by a printer and without it being necessary to stop the machine and to use other than a standard make ready.

Another object is to provide means whereby the printing pressure can be gauged accurately.

According to this invention a rotary printing machine comprises a main frame, a plate cylinder journalled in a and joining said second bearing blocks and a pair of base blocks, nuts on the upper and lower ends of said tension studs and bearing against the upper faces of said second bearing blocks and the lower faces of said base blocks respectively, coil springs between the lower faces of said second bearing blocks and the upper faces of said first bearing blocks, ap'air of lower seating blocks each intergral with one of said base blocks, a pair of upper seating blocks spaced from and vertically above said lower seating blocks and'capable of being moved vertically, members adapted to exert alternately predetermined high and low pressures between said upper and lower seating blocks, a pair of 'transversely movable' Wedge members between mating faces of said'upperseating blocks and the main frame and manually operable remote-control means to move said Wedge members to' adjust the position of said upper seating blocks thereby varying the movement of the second bearing blocks against the action of the coil springs and thus varying the pressure between the impression and plate cylinders during the application of said pressure. 7 i v Preferably the plate cylinder is provided with a gear wheel having a pitch circle radius slightly less than the overall radius ofthe plate cylinder with printingplates, which gear wheel is driven by a prime mover and drives the impression cylinder through the medium of a gear wheel associated with the latter when a printing pressure is not required and when said low pressure is applied between said seating blocks.

Preferably also the gear associated with the impression cylinder has a pitch circle radius equal to the radius of the impression cylinder and incorporates a slip mecha- Patented Sept. 1, 1959 nism whereby, when said high pressure is applied between said seating blocks, the plate cylinder is driven by its gear and drives the impression cylinder by friction between the surfaces of the plate and impression cylinders.

Preferably also means to measure the pressures between the impression and plate cylinders include an extensiometer adapted to record the linear stretch of the tension studs.

The invention is illustrated in the drawings accompanying the provisional specification, in which:

Figure 1 is a perspective diagrammatic view of one side of a rotary printing machine. It should be noted that complementary parts are to "be found on the other side of the machine.

Figure 2 is an enlarged sectional perspective view of part of the mechanism shown in Figure 1.

Referring to Figure 1, the mechanism includes an impression cylinder 11 and a plate cylinder 12 which latter carries printing plate (not shown) on not more than half its circumference. The impression cylinder 11 is journalled in a bearing block or housing 13 and the plate cylinder in a bearing block or housing 14 fast on a main frame 15; the bearing block 13 is adapted to slide between two surfaces 16, 17 of the said frame 15. Tension studs 18 and 19 connect the bearing block 13 with a base block 20 which also is capable of sliding vertically in the main frame. Coil springs 18 are arranged between the lower face of the bearing block 13 and the upper face of the plate cylinder bearing block 14, to lift the impression cylinder free of the plate cylinder when a printing pressure is not required. The studs 18 and 19 are secured to the blocks 13' and 20 by means of nuts and check nuts 21. A seating block 22 is mounted on and above base block 20 and spaced from and vertically above seating block 22 is seating block 23.

The opposing faces of the seating blocks 22 and 23 are grooved at 24 and 25 respectively. Pressure is applied to the seating'blocks 22 and 23 by means of toggles 26 and 27, which work in the grooves 24 and 25 respectively. The toggles are operated by a pair of connecting rods, one of which is indicated at 28, and are reciprocated by levers 29 mounted on a rocking shaft 30 which is driven by a cam arrangement (not shown) in the drive for the plate cylinder 12 in such a Way that the toggles 26 and 27 act upon the seating blocks 22 and 23 after each half revolution of the plate cylinder, so that the surfaces of the impression and platecylinders are alternately separated and brought together. A gear wheel is attached to the spindle of the plate cylinder and another gear wheel is freely mounted on the spindle of the impression cylinder, the ratio of the gears being 2:1.

' The plate cylinder has a slightly larger radius than that the manner described in the specification of our co-pendthe upper face of the wedge member 31 are horizontal but the bottom face of the wedge member 31 tapers towards the other side of the machine and the upper face of the setting block 23 is complementary with the tapering face of the wedge member so that the opposite faces are horizontal.

An adaptor plate 32 is bolted to the outside edge of the Wedge member 31 and is connected to and adapted to be moved by a screw 33. An externally threaded worm wheel 34, located between bearing plates 36, is mounted on the screw 33 and is adapted to be actuated through the medium of a worm 35. The worm forms part of a shaft 37 which is connected by way of shaft 38 (Figure 1) and universal couplings 39 to a hand wheel 40 which is carried in a bearing attached to the machine frame.

In order to vary the printing pressure by altering the distance between the centers of the impression and plate cylinders all that is necessary is for an adjustment to be 'made to the hand wheel 40. This results in movement being transmitted through the shaft 38 to the worm 35 on the shaft 37, thence to the worm Wheel 34 which causes movement of the screw 33 and thus of the wedge 31, in a desired direction. The result of such movement of the wedge is a change in the position of the seating block 23 and this results in a different pressure being obtained between the impression and plate cylinders when they are in mating contact one with another, since the position of seating block 23 changes with the position of the wedge 31 and the action of the toggles 26 and 27 brings about a corresponding change in the position of the seating block 22 and of the base block 20.

A device to indicate the degree of movement of the wedge member 31 comprises a flexible cable 41 anchored to the adaptor plate 32 and guided by pulleys 47, 48 to an indicating disc 49 freely mounted on the shaft of the hand wheel 40. The indicating disc 49 is provided with a stepped periphery round which the cable 41 passes. The end of the cable is connected to a spring 42 attached to the frame by a stud 43. Calibration of the disc 49 enables the position of the upper seating block 23 to be varied in accordance with a desired printing pressure during the period that the impression cylinder is friction driven by the plate cylinder.

An equivalent mechanism is provided on the other side of the machine.

In order to obtain a value for the printing pressure existing between the impression and plate cylinders an extensiometer device may be included to measure the stretch of the tension studs 18 and 19 between the bearing blocks 13 and the base blocks 20. As the bearing block 14 is fixed the pressure between the two cylinders is directly proportional to the stretch of the studs. A nonstressed steel rod 44 is attached to base block 20 by means of a mounting plate 45, and at its upper end to a thin spring steel strip which bears and acts upon the shock proof anvil of a dial gauge 46. The gauge indicates elastic deformation of the studs but can be calibrated to give relative impression pressure readings.

What is claimed is:

1. A rotary printing machine comprising a main frame, a first pair of bearing blocks fast with said main frame, a second pair of bearing blocks capable of movement between upper vertical parallel sliding surfaces on said main frame, a plate cylinder journalled in said first bearing blocks, an impression cylinder mounted above said plate cylinder and journalled in said second bearing blocks, a pair of base blocks, vertical tension studs passing through and joining said second bearing blocks to said blocks, nuts on the upper and lower ends of said tension studs and bearing against the upper faces of said second bearing blocks and the lower faces of said base blocks respectively, coil springs between the lower faces of said second bearing blocks and the upper faces of said first bearing blocks, a pair of lower seating blocks each integral with one of said base blocks, a pair of upper seating blocks spaced from and vertically above said lower seating blocks and capable of being moved vertically, members adapted to exert alternately predetermined high and low pressures between said upper and lower seating blocks, a pair of transversely movable wedge members between mating faces of said upper seating blocks and the main frame, and manually operable remote-control means to move said wedge members to adjust the position of said upper seating blocks, thereby varying the movement of said base blocks on application of said high pressure between said seating blocks, thereby varying the movement of the second bearing blocks against the action of the coil springs and thus varying the presure between the impression and plate cylinders during the application of said pressure.

2. A rotary printing machine as claimed in claim 1, in which the plate cylinder is provided with a gear wheel having a pitch circle radius slightly smaller than the overall radius of the plate cylinder with printing plates, which gear wheel is driven by a prime mover and drives the impression cylinder through the medium of a gear wheel associated with the latter when a printing pressure is not required and when said low pressure is applied between said seating blocks.

3. A rotary printing machine as claimed in claim 2,

in which the gear associated with the impression cylinder has a pitch circle radius equal to the radius of the impression cylinder and incorporates a slip mechanism whereby, when said high pressure is applied between said seating blocks, the plate cylinder is driven by its gear and drives the impression cylinder by friction between the surfaces of the plate and impression cylinders.

4. A rotary printing machine as claimed in claim 1, in which an extensiometer is provided to measure the pressures between the impression and plate cylinders by recording the linear stretch of the tension studs.

5. A rotary printing machine as claimed in claim 2, in which an extensiometer is provided to measure the pressures between the impression and plate cylinders by recording the linear stretch of the tension studs.

6. A rotary printing machine as claimed in claim 2, in which the gear associated with the impression cylinder has a pitch circle radius equal to the radius of the impression cylinder and incorporates a slip mechanism whereby, when said high pressure is applied between said seating blocks, the plate cylinder is driven by its gear and drives the impression cylinder by friction between the surfaces of the plate and impression cylinders, an extensiometer being provided to measure the pressures between the impression and plate cylinders by recording the linear stretch of the tension studs.

Bechman Mar. 14, 1933 Presby Aug. 27, 1940 

